JP3519311B2 - Synthetic resin pipe for cable protection - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mainly relates to a cable protecting synthetic resin tube used in an outer cable type post tension construction method.

[0002]

2. Description of the Related Art For example, as shown in FIG. 2, a tensioning cable used in a post tension construction method for a PC girder bridge has a through hole (2) (2) formed in each transverse girder (1) (1). The cable protection tube (3) is penetrated while being deflected at the through holes (2) and (2), and into the protection tube (3), as shown in FIG. Post tension is introduced into the concrete by inserting a plurality of cables (4) made of PC stranded wire and applying a predetermined tension to the cables (4). The protection tube (3) is filled with grout (6) such as cement mortar to protect the cable (4) from corrosion. (5) is
It is the main girder.

In the above, a black opaque polyethylene resin tube has been generally used as the cable protection tube (3).

[0004]

As described above, the grout filled in the cable protection tube (3) has the cable (4).
It protects the corroded material from corrosion, but the grout (6) needs to be closely packed in the protective tube (3) without any gap. For example, if there is an air layer or air bubbles between the protective tube (3) and the protective tube (3), dew condensation occurs at this portion, which causes rust corrosion of the cable (4) and significantly shortens the service life of the cable.

Therefore, it is desirable to be able to confirm on site whether or not the grout (6) has been reliably filled without any gaps. However, since the conventional protection tube is made of an opaque body as described above, it is necessary to fill the grout (6) with the same when the grout (6) is filled. In addition, there is a problem that the filling status cannot be visually recognized from the outside.

A method for solving such a problem is to form the cable protection tube (3) with a transparent body. However, when polyethylene resin is used as in the conventional case, such polyethylene resin is a crystalline resin. It has a drawback that it is difficult to obtain sufficient transparency.

In particular, the cable protection tube (3) used for the PC girder bridge of the above post-tensioning method has an appropriate flexibility so that it can be bent at the deflecting portion, and is still filled with the grout (6). It is necessary to have the strength to withstand the internal pressure of, and it is required to manufacture an inexpensive transparent protective tube while satisfying these requirements.

[0008] That is, an object of the present invention is to provide a transparent synthetic resin protective tube having an appropriate flexibility and a strength sufficient to withstand the internal pressure of the grout to be filled.

[0009]

In order to solve the above problems, the present invention provides a transparent synthetic resin tube containing a tensioning cable and having a grout filled therein.
With a tube wall of the synthetic resin tube and a soft portion and a hard portion, the soft portion is made of a transparent PVC resin comprising 40 parts of a plasticizer from 20, the tube wall of the synthetic resin tube
From the soft part that contains the hard part as a core material inside
It is characterized in that it is formed by spirally winding a strip-shaped body in the longitudinal direction of the tube .

Similarly, in the invention of claim 2 of this application,
In the above, the hard part contains a bit of plasticizer.
It is characterized by being a transparent polyvinyl chloride resin that does not contain or .

[0011]

[0012]

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION In FIG. 1, (11) is a strip-shaped body that constitutes the soft part of the present invention and is made of a soft synthetic resin, and the strip-shaped body (11) has A core material (12) made of a hard synthetic resin having an elliptical cross section is included over the entire length in the longitudinal direction. Then, the band-shaped body (11) is spirally wound while adhering or fusing the side edges of the band-shaped bodies (11) adjacent to each other, thereby forming the protective tube (3). .

In the above, a strip of soft synthetic resin (11)
Is a polyvinyl chloride resin as a base material, and contains 20 to 40 parts by weight, preferably 25 to 35 parts, of a plasticizer with respect to 100 parts of the base material resin. If there is more plasticizer than this, the entire tube will not be able to withstand the internal pressure of the grout and will extend in the axial direction and meander, while if it is less than the above amount, it will not be flexible enough to bend at the deflection part. It will be.

That is, by setting the amount of the plasticizer as described above, the entire protection tube (3) has appropriate flexibility, and the flexibility required when the outer cable type PC structure is used. In addition to the above, it is possible to obtain a grout that is strong enough to withstand the internal pressure of the grout when the grout is filled. Generally, the proportion of the plasticizer of this kind of soft polyvinyl chloride resin is 60 to 70 parts, but in the present invention, by reducing the proportion of the plasticizer to less than that,
The optimum one was obtained as a flexible cable protection tube having strength to withstand the internal pressure of the grout and flexibility.

As the plasticizer used, for example, DO
Typical examples of plasticizers for this type of polyvinyl chloride resin such as P (dioctyl phthalate), DBP (diptyl phthalate) and DOA (dioctyl adipate) can be used, and other types can also be used. .

In FIG. 1, the strip-shaped body (11) has a square or rectangular cross-section, but it is also possible to use a rhombus-shaped body in which both side surfaces are inclined parallel to each other.

On the other hand, the hard synthetic resin core material (12) which is the hard portion of the present invention is also made of a transparent body of polyvinyl chloride resin, and contains no or only a small amount of plasticizer. This ensures the necessary strength for the entire protection tube (3). The cross-sectional shape of this core material (12) is in addition to the elliptical shape,
The cross section may be a perfect circle, or various shapes such as a square, a triangle, and a rhombus.

In the above description, a hard polyvinyl chloride resin core material (12) is contained in a strip (11) made of a soft polyvinyl chloride resin to form a composite of a hard portion and a soft portion. Although shown, it is not limited to this, for example,
It may be formed by spirally winding a strip of a soft polyvinyl chloride resin and a strip of a hard polyvinyl chloride resin in a spiral direction so that they alternate in the longitudinal direction of the pipe.

[0020]

As described above, since the cable protection tube of the present invention is entirely transparent, the filling state of the grout can be easily visually recognized from the outside when the grout is filled inside. Since the filling operation can be performed while monitoring the formation of air bubbles and air layers inside the pipe, there is an effect that it is possible to prevent the cable from being corroded at an early stage and impairing the durability.

[0021] In the protecting tube of this invention, the tube wall of the synthetic resin tube and a soft portion and a hard portion, the soft portion is constituted by a transparent PVC resin comprising 40 parts of a plasticizer from 20 Therefore, it is possible to obtain the most suitable PC cable protection tube for the outer cable type post tension of the PC structure, which has an appropriate flexibility and strength while using an inexpensive polyvinyl chloride resin.

[Brief description of drawings]

FIG. 1 is a partial vertical cross-sectional view of a protective tube of the present invention.

FIG. 2 is a partial cross-sectional view of a post tension type PC girder bridge.

FIG. 3 is a cross-sectional view of a cable protection tube including a cable.

[Explanation of symbols]

(3) Cable protection tube (11) Band (12) Core material

─────────────────────────────────────────────────── ─── Continuation of front page (73) Patent holder 301013136 Wex Japan Co., Ltd. 2-30-6 Seta, Setagaya-ku, Tokyo (72) Inventor Hiroki Fukui 1-2-1 Sakaemachi, Takatsuki-shi, Osaka Totaku Kogyo Incorporated (72) Inventor Hiroyuki Tentsu 1-2-1, Sakaemachi, Takatsuki-shi, Osaka Totaku Kogyo Co., Ltd. (72) Inventor Yoshiyuki Tatsuda 1-2-1, Sakaemachi, Takatsuki, Osaka Totaku Kogyo Incorporated (72) Inventor Yasushi Sakane 1-2-1 Sakaemachi, Takatsuki City, Osaka Prefecture Totoku Kogyo Co., Ltd. (72) Inventor Tsutomu Sumiya 1273 Onna, Atsugi, Kanagawa Prefecture 313 (72) Inventor Norio Terada 1941-B7-102 Kamizuruma, Sagamihara City, Kanagawa Prefecture (56) References Japanese Unexamined Patent Publication No. 10-183755 (JP, A) Japanese Unexamined Patent Publication No. 52-14922 (JP, A) Japanese Utility Model No. 6-83816 (JP, U) ) (58) Fields surveyed (Int.Cl. ⁷ , DB name) E04C 5/10 E01D 1/00

Claims (2)

(57) [Claims] 1. A transparent synthetic resin tube having a tensioning cable contained therein and having grout filled therein, wherein the tube wall of the synthetic resin tube includes a soft portion and a hard portion, and The part is made of a transparent polyvinyl chloride resin containing 20 to 40 parts of a plasticizer, and the pipe wall of the synthetic resin pipe.
From the soft part that contains the hard part as a core material inside
A synthetic resin pipe for protecting a cable, which is formed by spirally winding a strip-shaped body in the longitudinal direction of the pipe. 2. A rotary hook in which the hard portion contains a small amount of plasticizer.
The synthetic resin pipe for cable protection according to claim 1, wherein the synthetic resin pipe is a transparent polyvinyl chloride resin that does not contain any resin.